A teardrop from Heaven: Aurora Australis

My lesson of the day: as it turns out, Good things do come to those who wait.

And boy, did we wait.

We had suffered the pain of seeing images of Aurora sent from Dumont Duville station, the South Pole and even The International Space Station (ISS), but none of our own.

Predicting Aurora

Our geographical location was in the centre of activity – that is to say we were frustratingly in the hole in the middle of the sugary donut of florid activity.

Predicting the Aurora

Things began to heat up – and insult followed injury – we even recieved reports of Aurora glistening over rural France!

But even as things began to heat up – and a momentous solar storm started – all remained disappointingly quiet above Concordia.  I put my head outside every night for the past two weeks.  The disappointment started to pile up.  We meandered round the station, dragging our feet and balls of disappointment behind.

Predicting the Aurora

Still nothing.

Having joined forces with Erick, station leader, we spent a few days fiddling, cursing and fiddling some more- setting up timelapse photography hoping to just capture some nice shots of the Milky Way – we returned home and I retired back to my lab to continue work.   Our ‘trap’ was set about 1 km away from the base.

Low and behold, it came – the Aurora Australis!

Better late than never

We must have been the last place in Antarctica to see Aurora, but I am not sure others have been given as a unique a view as this.

Living up in Northern Canada, I saw Aurora Borealis many times and in many forms, where Inuit have always believed that the Aurora were the spirits of their deceased relative, dancing like Nanuk.

The winds died down and the night became still.  The Milky Way grew strong and then pangs of green flew across the sky.  The whole station rushed outside – it was lucky the door didn’t lock behind us.

Teardrop from Heaven

Only for minutes, it was if Heaven opened up its windows and a teardrop fell from far and high above Concordia slicing through the darkness of the long, lonely polar night… we snapped a few photos before Heaven realised its mistake and closed its windows once again.

Photo by Alexander Kumar and Erick Bondoux. A teardrop from heaven: featuring Aurora Australis and Milky Way above Concordia Station, Antarctica (2012)

In the words of Bob Dylan, “You don’t need a weather man to know which way the wind blows”.

This photo resulted from the results of pure team work.  Bringing together two members of the team from two different countries, sharing equipment, to bring the best results – please enjoy the reward!

About Aurora

Aurorae were named after the Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas, by Pierre Gassendi in 1621.

An aurora (plural: aurorae or auroras) is a natural light display in the sky particularly in the high latitude (Arctic and Antarctic) regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere (thermosphere).

The charged particles originate in the magnetosphere and solar wind and, on Earth, are directed by the Earth’s magnetic field into the atmosphere.

Its southern counterpart, the aurora australis (or the southern lights), has almost identical features to the aurora borealis (northern lights) and is is visible from high southern latitudes in Antarctica, South America, New Zealand, and Australia.


How are Aurorae created?

Aurorae are associated with the solar wind, a flow of ions continuously flowing outward from the Sun. The Earth’s magnetic field traps these particles, many of which travel toward the poles where they are accelerated toward Earth. Collisions between these ions and atmospheric atoms and molecules cause energy releases in the form of auroras appearing in large circles around the poles. Auroras are more frequent and brighter during the intense phase of the solar cycle when coronal mass ejections increase the intensity of the solar wind

Where do Aurorae get their colour?

Auroras result from emissions of photons in the Earth’s upper atmosphere, above 80 km (50 mi), from ionized nitrogen atoms regaining an electron, and oxygen and nitrogen atoms returning from an excited state to ground state.  They are ionized or excited by the collision of solar wind and magnetospheric particles being funneled down and accelerated along the Earth’s magnetic field lines; excitation energy is lost by the emission of a photon, or by collision with another atom or molecule:

- Oxygen emissions: green or brownish-red, depending on the amount of energy absorbed

- Nitrogen emissions: blue or red; blue if the atom regains an electron after it has been ionized, red if returning to ground state from an excited state.

Because the very top of the atmosphere has a higher percentage of oxygen and is sparsely distributed such collisions are rare enough to allow time for oxygen to emit red.  Collisions become more frequent progressing down into the atmosphere, so that red emissions do not have time to happen, and eventually even green light emissions are prevented.

This is why there is a color differential with altitude; at high altitude oxygen red dominates, then oxygen green and nitrogen blue/red, then finally nitrogen blue/red when collisions prevent oxygen from emitting anything. Green is the most common of all auroras.

Behind it is pink, a mixture of light green and red, followed by pure red, yellow (a mixture of red and green), and lastly, pure blue.

Life on Mars

Incredibly, Aurorae occur on other planets!

Similar to the Earth’s aurora, they are visible close to the planet’s magnetic poles.  Imagine that – it must be incredible.  One day man will orbit and even stand on Mars and they too will be entertained by this natural wonder!

To inspire your imagination further, here is a view from the International Space Station:

Aurora Australis, as pictured from ISS (Mission 28)

 

Song of the Day:

‘Across the Universe’ by the Beatles

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